Diagnostic utility of ASL‐MRI and FDG‐PET in the behavioral variant of FTD and AD

Abstract

ObjectiveTo compare the values of arterial spin‐labeled (ASL) MRI and fluorodeoxyglucose (FDG) PET in the diagnosis of behavioral variant of frontotemporal dementia (bvFTD) and Alzheimer's disease (AD).MethodsPartial least squares logistic regression was used to identify voxels with diagnostic value in cerebral blood flow (CBF) and cerebral metabolic rate of glucose (CMRgl) maps from patients with bvFTD (n = 32) and AD (n = 28), who were compared with each other and with cognitively normal controls (CN, n = 15). Diagnostic values of these maps were compared with each other.ResultsRegions that differentiated each disorder from controls were similar for CBF and CMRgl. For differentiating AD from CN, the areas under the curve (AUC) for CBF (0.89) and CMRgl (0.91) were similar, with similar sensitivity (CBF: 86%, CMRgl: 78%) and specificity (CBF: 92%, CMRgl: 100%). Likewise, for differentiating bvFTD from CN performances of CBF (AUC = 0.83) and CMRgl (AUC = 0.85) were equivalent, with similar sensitivity (CBF: 78%, CMRgl: 79%) and specificity (CBF: 92%, CMRgl: 100%). In differentiating bvFTD from AD, classification was again similar for CBF (AUC = 0.87) and CMRgl (AUC = 0.79), as were sensitivity (CBF: 83%, CMRgl: 89%) and specificity (CBF: 93%, CMRgl: 78%). None of the differences in any performance measure were statistically significant.InterpretationASL‐MRI has similar diagnostic utility as FDG‐PET in the diagnosis of AD and bvFTD. Continued development of ASL‐MRI as a diagnostic tool for neurodegenerative dementias is warranted.

A longitudinal characterization of perfusion in the aging brain and associations with cognition and neural structure

“…Consistent results have been observed between [ 15 O]water PET and ASL (Feng et al, 2004;Ye et al, 2000). Furthermore, joint analyses of [ 18 F]FDG-PET and ASL acquisition have confirmed a good overall correlation between perfusion and glucose uptake in controls (Cha et al, 2013), as well as in patients with AD (Chen, Wolk, et al, 2011), Lewy body dementia (Nedelska et al, 2018), and frontotemporal dementia (Tosun et al, 2016). Recent work has shown relatively strong correlations between ASL imaging and relative perfusion (R1) quantified during dynamic Pittsburgh Compound B (PiB) PET imaging in carriers of autosomal dominant AD mutations (Yan et al, 2018).…”

“…Because of neurovascular coupling, glucose consumption is tightly coupled with CBF (Baron et al, 1982;Furlow, Harrison, & Harrison, 1983), and [ 18 F]FDG-PET and [ 15 O]water PET are highly correlated (Bentourkia et al, 2000;Fox, Raichle, Mintun, & Dence, 1988). Furthermore, joint analyses of [ 18 F]FDG-PET and ASL acquisition have confirmed a good overall correlation between perfusion and glucose uptake in controls (Cha et al, 2013), as well as in patients with AD (Chen, Wolk, et al, 2011), Lewy body dementia (Nedelska et al, 2018), and frontotemporal dementia (Tosun et al, 2016). In ASL imaging, rather than using a radioactive tracer as a label, protons in the blood are labeled with a radiofrequency pulse; the perfusion of these magnetically-tagged protons to each voxel of the brain is then recorded.…”

The FTD‐like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism

“…However, it is still controversially discussed, whether neurons or astrocytes are the main consumers of glucose in the brain (Mergenthaler et al, 2013). In previous studies, it has been shown that during neurodegeneration, the pattern of CBF and metabolic deficits occur in parallel in AD and FTD patients (Verfaillie et al, 2015), and ASL-MRI has similar diagnostic utility as FDG-PET in both AD and FTD (Tosun et al, 2016). In previous studies, it has been shown that during neurodegeneration, the pattern of CBF and metabolic deficits occur in parallel in AD and FTD patients (Verfaillie et al, 2015), and ASL-MRI has similar diagnostic utility as FDG-PET in both AD and FTD (Tosun et al, 2016).…”

Neuroimaging in Dementia

“…Preliminary evidence suggests that ASL perfusion imaging may help to distinguish bvFTD from other groups with sensitivity and specificity similar to FDG-PET. 106 For example, sensitivity and specificity for ASL to distinguish bvFTD from AD were 83% and 93%, respectively, compared with 89% and 78% for FDG-PET. Although FDG-PET often can be useful in helping to differentiate bvFTD from AD, frontotemporal hypometabolism can occur in frontal variants of AD as well as in primary psychiatric disorders, both of which can clinically resemble bvFTD.…”